... neighbouring Yantai Port, to south next to Yantai Airport, with beautiful scenery, comfortable climate and convinent traffic. Furthermore, ... rod coupling, subcoupling, polished rod coupling,slim hole(SH) coupling,class SM coupling. Spraying Metal coupling combines top quality steel with ... steel pipe in accord with API standard. This is API Sucker Rod Coupling, class SM,with large chamfer1)Material: Good ...